Haptoglobin polymorphism correlated with coronary artery disease

Introduction: Haptoglobin polymorphism has been correlated with disease and some studies have associated the Hp2 allele with susceptibility to or protection against certain infectious (pulmonary tuberculosis, HIV) and non-infectious (diabetes, coronary artery disease, obesity) diseases. The aim of this study was to verify possible correlations of haptoglobin genotypes and subtypes by comparing coronary artery disease (CAD) patients with blood donors.
Material and methods: Haptoglobin genotypes and subtypes were analyzed by DNA amplification with the DraI restriction enzyme, in 125 CAD patients diagnosed by coronary angiography, and 125 blood donors as matched healthy controls.
Results: The distribution of haptoglobin genotypes was similar in the groups, without significant statistical differences (p = 0.643). The Hp2/Hp2 genotype was more frequent in both the CAD group and blood donors followed by Hp2/Hp1 and Hp1/Hp1. The allele frequency of Hp2 was higher than Hp1 in the groups. The results showed a significant difference (p = 0.002) between the groups regarding haptoglobin subtypes; Hp2FS/Hp2FS was prevalent in both groups with the least frequent subtype being Hp2FF/Hp2FF for CAD patients and Hp1F/Hp1S among blood donors. There was a statistically significant difference (p = 0.027) between the frequencies of the commonest allele subtype, Hp2FS, and the least common, Hp2FF.
Conclusions: Unlike blood donors, the Hp2FF/Hp2FF haptoglobin subtype was the least frequent among CAD patients, which may implicate this subtype in the development of CAD, a disease with a high mortality rate which consequently reduces the proportion of these individuals in populations.